1、Best Practices Entry: Best Practice Info:a71 Committee Approval Date: 2000-03-03a71 Center Point of Contact: JPLa71 Submitted by: Wil HarkinsSubject: Critical Design Review for Unmanned Missions Practice: Practice: Conduct a formal Critical Design Review (CDR) of hardware, software, and firmware at
2、the subsystem and system levels. Schedule the review prior to the start of subsystem fabrication and assembly to assure that the design solutions satisfy the performance requirements established in the development specifications. Establish this review as a standard reliability engineering practice f
3、or flight hardware.Abstract: Preferred Practice for Design from NASA Technical Memorandum 4322A, NASA Reliability Preferred Practices for Design and Test.Benefits:The Critical Design Review (CDR) provides increased assurance that the proposed design, and the planned manufacturing and test methods an
4、d procedures, will result in an acceptable product, with minimal project risk.Implementation Method:ResponsibilitiesThe responsible project or task manager defines the need to conduct a formal review and initiates action by contacting the convening authority (generally, the next higher management le
5、vel). The convening authority, in consultation with the responsible manager, appoints the review board and a chair and defines the board charter and schedule.The CDR ensures that all design considerations have been adequately incorporated and that all engineering analyses have been completed. Result
6、s of engineering model tests are presented to demonstrate that the hardware and software can be built to perform as planned. In addition, plans are presented for fabrication and testing, including qualification and acceptance.The review board, under direction of the chair, conducts the review and pr
7、epares a written report to the responsible manager on the findings and recommendations. The responsible manager then prepares a written response to the convening authority addressing the disposition of the review board findings and recommendations. The convening authority reviews and approves these
8、dispositions.CDR AgendaThe following items and issues are addressed at the CDR, where applicable:1. Functional description and block diagram.2. Functional requirements and compliance of the design, presented in matrix format with traceability references.Provided by IHSNot for ResaleNo reproduction o
9、r networking permitted without license from IHS-,-,-3. Disposition of subassembly/subsystem Preliminary Design Review (PDR) action items.4. Compliance of the design with accuracy requirements.5. Compliance of the design with interface requirements.6. Compliance of the design with mass requirements.7
10、. Compliance of the design with power requirements.8. Compliance of the design with memory requirements.9. Compliance of the design with environmental requirements.10. Compliance of the design with project Single Point Failure (SPF) policy.11. Compliance of the design with maintainability requiremen
11、ts.12. Status and plans for electronic piece part acquisition.13. Make or buy decisions and rationale.14. Compliance with project requirements for inherited hardware and software. Consideration of inheritance review results.15. Plans for compliance with spares requirements.16. Status of plan for mee
12、ting quality assurance requirements, procedures, and workmanship standards.17. Status of plan for meeting software assurance requirements.18. Status or results of plan for meeting reliability analyses requirements.19. Status or results of plan for meeting safety analyses requirements.20. Status of p
13、lan for meeting documentation requirements.21. Status of plan for meeting support equipment requirements.22. Status or results of plan for meeting structural analysis requirements.23. Status or results of plan for meeting thermal analysis requirements.24. Fabrication, assembly, and test schedule and
14、 constraints.25. Status or results of plan for meeting calibration requirements.26. Plans for compliance with testability requirements.27. Qualification (protoflight) test requirements and implementation plans.28. Acceptance test requirements and plans.29. Manufacturing and test facility requirement
15、s, availability and acceptability. Certification status and plans.30. Hazardous operations facility requirements, availability and acceptability. Certification status and plans.31. Results of detailed peer reviews, conclusions, and implementation plans.Technical Rationale:The CDR provides for the as
16、sessment of the design and fabrication plans by a group of knowledgeable persons not directly involved in the activity being reviewed. A formal review can focus many years of experience on the subject at hand.The CDR aids the responsible manager in evaluating the quality of the work and in making im
17、portant decisions, including those concerning completion of critical milestones and resolution of identified issues. The review process should aid in the identification of problems and the evaluation of design Provided by IHSNot for ResaleNo reproduction or networking permitted without license from
18、IHS-,-,-approaches and options.Related Practices:1. Preliminary Design Review, Reliability Preferred Practice No. PD-ED-1215.1.2. Subsystem Inheritance Review, Reliability Preferred Practice No. PD-ED-1262.3. Common Review Methods for Engineering Products, Reliability Preferred Practice No. PD-ED-12
19、15.4References:1. JPL Standard Practice Instruction (SPI) 4-16-1.2. Guidelines for Planning and Conducting Formal Reviews, Jet Propulsion Laboratory document JPL D-10401 (Office of Engineering and Mission Assurance).3. Technical Reviews and Audits for Systems, Equipment and Computer Software, MIL-ST
20、D-1521 (USAF).Impact of Non-Practice: Impact of Non-Practice: In the absence of a CDR, potential problems with adverse impacts on the subsystem, system, or project may not be identified in a timely manner. This oversight may later result in a condition having a significant effect on quality, reliabi
21、lity, capability, schedule, or cost.Related Practices: N/AAdditional Info: Approval Info: a71 Approval Date: 2000-03-03a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
